Detection of Fasciola Coproantigens Using Polyclonal Antibodies Produced Against Fasciola hepatica and Fasciola gigantica Secretory Excretory Antigens

Parasitological methods for diagnosing fascioliasis have limitations such as; Intermittent excretion of parasite eggs is the long stage of presence of parasite eggs in the feces. Also, serological methods based on the detection of antiparasitic antibodies are not able to distinguish past infections from new infections, so the detection of parasitic co-antigens is more reliable than other diagnostic methods. Therefore, the aim of the present study was to determine and detect Fasciola coproantigens using polyclonal antibodies produced against Fasciola hepatica and Fasciola gigantica secretory excretory antigens.

In the present experimental study conducted in 2016-2017, adult Fasciola worms were collected from the livers of infected animals and species were determined by molecular method of enzymatic digestion. Excretory-secretory antigen was prepared from both Fasciola species. In order to produce polyclonal antibodies, 2 rabbits were immunized for each antigen. IgG antibodies produced were purified by affinity chromatography and conjugated with peroxidase enzyme. Coproantigens from 99 animal fecal samples included; 30 samples infected with Fasciola, 39 samples with other parasitic diseases and 30 healthy samples were prepared. In the present study, two ELISA sandwich systems were designed and evaluated using polyclonal antibodies produced to identify Fasciola co-antigen. Statistical characteristics of the tests were calculated using Medical Collector 16.4.3 software. Kappa coefficient and consistency check between ELISA sandwich tests were calculated using SPSS software version 20.

Sandwich ELISA test using polyclonal antibodies produced against Fasciola hepatica and Fasciola gigantica secretory antigens showed 96.67%, 89.86% and 96.67% and 91.3%, respectively. Moreover, a high agreement (kappa coefficient <0.9) was observed between polyclonal antibodies produced against both Fasciola species for the diagnosis of fascioliasis.

Overall, the findings indicated that polyclonal antibodies produced against excretory-secretory antigens of both Fasciola species have good efficacy for detection of Fasciola co-antigens and diagnosis of fascioliasis.